NBC News correspondent Tamron Hall for the first time revealed details about the unsolved murder of her sister at a Television Critics Association panel for Investigation Discovery on Thursday morning — and stayed firm in response to a critic who dismissed her story to get to his point.

Philadelphia TV critic Jonathan Storm asked Hall how she split her time between her full duties for NBC News — which include anchoring “NewsNation” daily on MSNBC — and investigating and reporting for “Deadline: Crime with Tamron Hall” on ID.

The host responded with an intimate story to illustrate why she finds it so important to dedicate time to the Investigation Discovery show, even with the demands of her day job.

Viewers of “Deadline: Crime,” which starts its second season this spring, are familiar with the story — Hall described the horrible day when she got the call that her sister had been found face down in her pool.

Initially called an accident, a detective told Hall that that was not so. Hall’s sister had bruising all over her body, hair ripped from her scalp, and most of her fingernails were gone.

Officers told the family they were fairly sure who committed the crime, but nobody was ever brought to justice.

“One day turned to two; two days turned to a month,” Hall said.

The TCA audience was visibly moved, but Storm responded, “That’s all very nice, but can you answer my question?”

Before carrying on with her story, Hall responded to Storm’s comment, saying, “It’s not ‘nice,'” and asking him how he would feel if he got a call telling him his sister had been beaten and murdered.

For the first time, Hall shared details about the events leading to her sister’s death to drive the point home. She said there were signs of domestic abuse that she recognized at the time but did nothing to intervene, and she partly blames herself for the family’s loss.

Hall said the tendency to go back to dangerous situations is what makes the cycle of violence so difficult to stop and what keeps bringing stories like hers to the show.

“It’s not as easy as saying, ‘Why don’t kids get it?’… It’s not as simple as saying ‘What could I have done differently?'”

Hall credited her personal experience for the drive she has to host “Deadline: Crime with Tamron Hall” on the network, which requires her to split her time with her NBC reporting and MSNBC anchor duties. But Hall said she is still not ready to tell her sister’s story on the show.